1. Field of the Invention
The present invention relates to an optical fiber connector, and more particularly, to an optical fiber connector for collectively connecting a plurality of optical fibers together.
2. Description of the Related Art
In an optical fiber communication system, an optical fiber connector is used to connect optical fibers together. There are conventionally known optical fiber connectors such as a multi-core optical fiber connector for collectively joining a plurality of optical fibers together, in addition to a single-core optical fiber connector. FIG. 1 shows a general multi-core optical fiber connector. Tip ends of the optical fibers 62, 62 in tapelike optical fiber cables 60, 60 are collectively connected together by such multi-core optical fiber connector.
The multi-core optical fiber connector comprises a lower plate 10 and a holding plate 80. The lower plate 10 is provided with a plurality of V-grooves 12 formed therein for accommodating the plurality of optical fibers 62 in an arranged manner, and an accommodation groove 16 defined to communicate with ends of the V-grooves 12 for disposition of a covering portion 64 of the optical fiber cable 60. Alignment grooves 14 are defined on both sides of the V-grooves 12 for respectively holding alignment pins (not shown) to position the lower plates 10 relative to each other. The holding plate 80 is provided with an accommodation groove 84 corresponding to the accommodation groove 16, and alignment grooves 82 corresponding to the alignment grooves 14.
The optical fibers 62 are disposed in the V-grooves 12 in the lower plate 10, and the covering portion 64 of the optical fiber cable 60 is disposed in the accommodation groove 16. In this condition, the holding plate 80 is laid on the lower plate 10, and the lower plate 10, the holding plate 80, the covering portion 64 and the optical fibers 62 are integrally secured together by use of an adhesive. The multi-core optical connectors are positioned by means of the alignment pins (not shown) integrally inserted into the alignment grooves 14 and 8, with the end faces of the optical fibers 62 being connected together.
In such a multi-core optical connector, it is necessary to reduce variations in connection loss due to misalignment of the optical fibers 62 and due to a variation in temperature, as much as possible. For this reason, it has been proposed to make lower plate 10 and the holding plate 80 of ceramics, to cut the V-grooves 12 and the alignment grooves 14 with high machining accuracy in the lower ceramic plate 10, and to cut the alignment grooves 82 with high machining accuracy in the ceramics holding plate 80.
When the lower ceramics plate 10 is machined, however, the V-grooves 12 are first made in the entire upper surface of the lower ceramics plate 10 and then, the portions of the V-grooves 12 corresponding to a section for accommodating the covering portion 64 and an upper portion of the lower ceramics plate 10 are removed by counterboring, thereby providing the accommodation groove 16.
A significantly long time is required for performing this counterboring, thereby causing a considerably increased machining cost for the lower ceramics plate 10, resulting in an expensive multi-core optical connector as a whole. Moreover, the accommodation groove 16 is adapted for merely accommodating the covering portion 64 therein and is not a portion requiring accuracy, and nevertheless, it accounts for a significant portion of the machining cost for the lower ceramics plate 10. Further, it is necessary to define the V-grooves 12 first in the entire surface of the lower ceramics plate including a section corresponding to the accommodation groove 16 which will be removed later, and hence, an unnecessary machining cost is taken even for provision of the V-grooves 12.